Systems and methods for idle coasting management

ABSTRACT

A system, method, and apparatus includes management of coasting during operation of a vehicle. Speed of a vehicle is monitored during a coasting event and is compared against a threshold to determine whether to remain coasting or re-engage an engine to a driveline. If instantaneous speed exceeds the threshold, predicted speed can be used to determine whether to permit short duration excursions, or to re-engage the engine to the driveline. These techniques can be used whether the vehicle is slowing down below a threshold or speeding up above a threshold.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of International PatentApplication No. PCT/US16/59694 filed on Oct. 31, 2016, which claims thebenefit of the filing date of U.S. Provisional Application No.62/248,728 filed on Oct. 30, 2015, each of which is incorporated hereinby reference in its entirety for all purposes.

BACKGROUND

The present application relates generally to management of coasting in avehicle for fuel economy improvement, and more particularly to idlecoasting management of a vehicle with a manual transmission.

Improved fuel economy for vehicles can be obtained by allowing thevehicle to coast during certain operating and drive cycle conditions.However, these benefits are not heretofore realized with all vehicles,such as those with manual transmissions, where the operator has controlover the gear selection. Therefore, there remains a significant need forthe apparatuses, methods and systems disclosed herein.

DISCLOSURE

For the purposes of clearly, concisely and exactly describing exemplaryembodiments of the invention, the manner and process of making and usingthe same, and to enable the practice, making and use of the same,reference will now be made to certain exemplary embodiments, includingthose illustrated in the figures, and specific language will be used todescribe the same. It shall nevertheless be understood that nolimitation of the scope of the invention is thereby created, and thatthe invention includes and protects such alterations, modifications, andfurther applications of the exemplary embodiments as would occur to oneskilled in the art.

SUMMARY

One example of a system, method, and apparatus includes a manualtransmission that is configured to automatically allow the vehicle tocoast with the engine disengaged from the driveline at certain drivecycle conditions. Whether the engine remains disengaged from thedriveline depends on monitoring speed of vehicle and comparing itagainst a cancellation delta that can be determined as a function ofroad grade.

This summary is not intended to identify key or essential features ofthe claimed subject matter, nor is it intended to be used as an aid inlimiting the scope of the claimed subject matter. Further embodiments,forms, objects, features, advantages, aspects, and benefits shall becomeapparent from the following description and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic illustration of a vehicle with a controllablemanual transmission for coasting management of the vehicle.

FIG. 2 is a schematic illustration of a controller for coastingmanagement of a vehicle.

FIG. 3a is a schematic of a vehicle on a downhill grade.

FIG. 3b is a depiction of whether an engine is engaged with a driveline.

FIG. 3c depicts a speed profile.

FIG. 3d depicts a fueling profile.

FIG. 4a is a depiction of whether an engine is engaged with a driveline.

FIG. 4b depicts a speed profile.

FIG. 5 depicts an embodiment of various cases using predicted speed.

FIG. 6a is a schematic of a vehicle on a downhill grade.

FIG. 6b is a depiction of whether an engine is engaged with a driveline.

FIG. 6c depicts a speed profile.

FIG. 6d depicts a fueling profile.

FIG. 7 depicts an embodiment of various cases using predicted speed.

FIG. 8 depicts an embodiment of various cases using predicted speed.

FIG. 9 is a block diagram of an embodiment of ICM.

FIG. 10 is a depiction of Idle Coasting without Horizon.

FIG. 11 is a depiction of Idle Coasting without Horizon.

FIG. 12 depicts a block diagram implementation of one embodiment of IdleCoasting without Horizon.

FIG. 13 depicts aspects of ICM with Horizon.

FIG. 14 depicts aspects of ICM with Horizon.

FIG. 15 depicts a block diagram implementation of one embodiment of IdleCoasting with Horizon.

FIG. 16 depicts a block diagram implementation of one embodiment of IdleCoasting with Horizon.

FIG. 17 depicts an embodiment of Idle Coasting with Horizon.

FIG. 18 depicts an embodiment of Idle Coasting with Horizon.

FIG. 19 depicts an embodiment of “Enable Conditions.”

FIG. 20 depicts an embodiment of “Speed Protection.”

FIG. 21 depicts an embodiment of “Speed Protection.”

FIG. 22 depicts an aspect of one embodiment of “Speed Protection.”

FIG. 23 depicts an embodiment of the Keep Disengaged Criterion.

FIG. 24 depicts an embodiment of Early Re-engage Zone 1 Criterion.

FIG. 25 depicts an embodiment of Early Re-engage Zone 3 Criterion.

FIG. 26 depicts possible values for a number of variables used herein.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

With reference to FIG. 1, there is illustrated a schematic view of anexemplary vehicle 100 including a powertrain 102 incorporated withinvehicle 100. In the illustrated embodiment, the powertrain 102 includesan engine 104, such as an internal combustion engine, structured togenerate power for the vehicle 100. The powertrain 102 further includesa transmission 106 connected to the engine 104 for adapting the outputtorque of the engine 104 and transmitting the output torque to adriveline 107 including drive shaft 108. In certain embodiments, thetransmission 106 is a manual transmission that may be disengageablyconnected to an engine crankshaft 105 via a clutch 109.

In the rear wheel drive configuration illustrated for vehicle 100, thedriveline 107 of powertrain 102 includes a final drive 110 having a reardifferential 112 connecting the drive shaft 108 to rear axles 114 a, 114b. It is contemplated that the components of powertrain 102 may bepositioned in different locations throughout the vehicle 100. In onenon-limiting example of a vehicle 100 having a front wheel driveconfiguration, transmission 106 may be a trans axle and final drive 110may reside at the front of the vehicle 100, connecting front axles 116 aand 116 b to the engine 104 via the transaxle. It is also contemplatedthat in some embodiments the vehicle 100 is in an all-wheel driveconfiguration.

In the illustrated embodiment, vehicle 100 includes two front wheels 122a, 122 b mounted to front axles 116 a, 116 b, respectively. Vehiclesystem 100 further includes two rear wheels 126 a, 126 b mounted to rearaxles 114 a, 114 b, respectively. It is contemplated that vehicle 100may have more or fewer wheels than illustrated in FIG. 1. Vehicle 100may also include various components not shown, such a fuel systemincluding a fuel tank, a front differential, a braking system, asuspension, an engine intake system and an exhaust system, which mayinclude an exhaust aftertreatment system, to name a few examples.

Vehicle 100 includes an electronic or engine control unit (ECU) 130,sometimes referred to as an electronic or engine control module (ECM),or the like, which is directed to regulating and controlling theoperation of engine 104. A transmission control unit (TCU) 140 isillustrated in vehicle 100, which is directed to the regulation andcontrol of transmission 106 operation. ECU 130 and TCU 140 are each inelectrical communication with a plurality of vehicle sensors (not shown)in vehicle 100 for receiving and transmitting conditions of vehicle 100,such as temperature and pressure conditions, for example. In certainembodiments, the ECU 130 and the TCU 140 may be combined into a singlecontrol module, commonly referred to as a powertrain control module(PCM) or powertrain control unit (PCU), or the like. It is contemplatedthat ECU 130 and/or TCU 140 may be integrated within the engine 104 ortransmission 106, respectively. Other various electronic control unitsfor vehicle subsystems are typically present in vehicle system 100, suchas a braking system electronic control unit and a cruise controlelectronic control unit, for example, but such other various electroniccontrol units are not show in vehicle 100 to preserve clarity.

Vehicle system 100 further includes a cycle efficiency management (CEM)module 150, which may be directed to the control of the operationsdescribed herein and/or directed toward an intermediary control for theregulation and control of the powertrain 102 in vehicle system 100. Inthe illustrated embodiment, CEM module 150 is in electricalcommunication with each of the ECU 130 and TCU 140. In certainembodiments, at least a portion of the CEM module 150 may be integratedwithin the ECU 130 and/or TCU 140. CEM module 150 may further be inelectrical communication with one or more of the plurality of vehiclesensors in vehicle 100 for receiving and transmitting conditions ofvehicle 100, such as temperature and pressure conditions, routeconditions, terrain conditions, speed conditions, and weatherconditions, for example. It is contemplated that at least a portion ofthe conditions and/or measured inputs used for interpreting signals bythe CEM module 150 may be received from ECU 130 and/or TCU 140, inaddition to or alternatively to the plurality of vehicle sensors.Furthermore, the CEM module 150 may include a processor or controllerand be a control unit.

The CEM module 150 includes stored data values, constants, andfunctions, as well as operating instructions stored on, for example, acomputer readable medium. Any of the operations of exemplary proceduresdescribed herein may be performed at least partially by the CEM module150. In certain embodiments, the controller includes one or more modulesstructured to functionally execute the operations of the controller. Thedescription herein including modules emphasizes the structuralindependence of the aspects of the CEM module 150, and illustrates onegrouping of operations and responsibilities of the CEM module 150. Othergroupings that execute similar overall operations are understood withinthe scope of the present application. Modules may be implemented inhardware and/or instructions on computer readable medium, and modulesmay be distributed across various hardware or computer readable mediumcomponents. More specific descriptions of certain embodiments ofcontroller operations are included in the section referencing FIG. 2.Operations illustrated are understood to be exemplary only, andoperations may be combined or divided, and added or removed, as well asre-ordered in whole or part, unless stated explicitly to the contraryherein.

Certain operations described herein include operations to interpret oneor more parameters. Interpreting, as utilized herein, includes receivingvalues by any method known in the art, including at least receivingvalues from a datalink or network communication, receiving an electronicsignal (e.g., a voltage, frequency, current, or pulse-width modulation(PWM) signal) indicative of the value, receiving a software parameterindicative of the value, reading the value from a memory location on acomputer readable medium, receiving the value as a run-time parameter byany means known in the art, and/or by receiving a value by which theinterpreted parameter can be calculated, and/or by referencing a defaultvalue that is interpreted to be the parameter value.

One exemplary embodiment of CEM module 150 is shown in FIG. 2. The CEMmodule 150 may include an engine fueling map 210, an enginebraking/friction map 212, and a coasting management module 220, amongother modules. Example other modules include an operations cost module,a vehicle speed management module, a fuel quantity management module, atransient torque management module, a transmission arbiter module, acruise control arbiter module, a throttle arbiter module, and anoperator override module. Other arrangements that functionally executethe operations of the CEM module 150 are contemplated in the presentapplication. For example, additional CEM module and cruise controloperation aspects with which the present invention may have applicationmay be found with reference to U.S. Provisional Application Ser. No.61/941,850 filed on Feb. 19, 2104, and U.S. patent application Ser. No.14/261,010 filed on Apr. 24, 2014, each of which is incorporated hereinby reference for all purposes.

In certain embodiments, the CEM module 150 receives operating inputs200, such as a fuel amount input, a weather conditions input from one ormore sensors and/or one or more external devices for detecting weatherconditions, and a route conditions input from one or more sensors and/orone or more external devices for detecting route conditions. The fuelamount may include the amount of fuel remaining in the fuel tank. Theweather conditions may include a humidity level, a wind condition, and aprecipitation condition. The route conditions may include a tripdistance, an elevation profile, a route grade profile, a grade length, amaximum speed limit, a minimum speed limit, a traffic condition, and aroad condition.

The CEM module 150 illustrated in FIG. 2 includes engine conditions 280input from the ECU 130 and transmission conditions 290 input from theTCU 140. In certain embodiments, the engine conditions 280 andtransmission conditions 290 may be determined from a plurality ofsensors positioned throughout vehicle 100. Engine conditions 280 mayinclude a brake actuation parameter, a throttle position parameter, atorque request parameter, an ambient air pressure, an ambient airtemperature, an engine temperature, an engine torque, an engine speed,an engine speed rate of change, an engine degrade state, and a brakeposition. Transmission conditions 290 may include a transmission gearratio, a current transmission gear, a final drive ratio, a clutchactuator position, and a neutral gear state.

In operation, CEM module 150 is a tool based on a series of operationcontrol modules that provide both anticipated and currently desiredvehicle 100 operation behavior to optimize fuel economy. The series ofoperation control modules are focused on the components of vehicle 100,and more specifically the components of powertrain 102. For a giventravel route and one or more route constraints, the recommendations oroutputs made by the CEM module 150 is dependent on the operating inputs200, engine conditions 280, transmission conditions 290, the enginefueling map 210 and the engine braking/friction map 212. Maps 210, 212may be in the form of multidimensional performance maps, or lookuptables, calibrated offline and provided by the engine manufacturer. Itis contemplated that in certain embodiments the engine fueling map 210may be obtained from the engine braking/friction map 212, while in otherembodiments the engine braking/friction map 212 may be obtained from theengine fueling map 210.

CEM module 150 is operable to assume active control of the vehicle 100,regulating a vehicle speed, the engine torque curve, and/or otherpowertrain 102 operating conditions to ensure optimal vehicle 100operation, or passive control which allows the operator to takerecommended actions. In the present application, CEM module 150 includescoasting management module 220 operable to interpret operating inputs200, engine conditions 280, and transmission conditions 290 to determineif a coasting opportunity 222 is available, and to automatically(without operator input) disconnect the engine 104 from the driveline107 in a vehicle with a manual transmission 106 to enable coasting ofvehicle 100 to obtain, for example, fuel economy benefits.

In response to coasting management module 220 interpreting or receivingan input that a coasting opportunity is available for vehicle 100 aredesired, CEM module 150 outputs, in a first embodiment, a transmissiongear command 250 to TCU 140 or, in a second embodiment, a clutchactuator command 260 to TCU 140. Transmission gear command 250 andclutch actuator command 260 each disengage engine 104 from driveline 107in response to coasting opportunity 222 to provide coasting operation ofvehicle 100.

In one embodiment, transmission gear command 250 controls an actuator119 (shown in FIG. 1 as located within the contours of the manualtransmission 106, but it will be appreciated that the actuator 119 canbe located elsewhere) that actuates transmission 106 to achieve aneutral gear position to disconnect engine 104 from driveline 107. Inanother embodiment, clutch actuator command 260 actuates a clutchactuator 111 associated with clutch 109 to disengage clutch 109 anddisconnect engine 104 from driveline 107. Transmission 106 gear command250 or clutch actuator command 260 can be activated by CEM module 150during cruise control operation of vehicle 100, or anytime when CEMmodule 150 is active for controlling operations of vehicle 100 inresponse to certain conditions. Transmission gear command 250 or clutchactuator command 260 can be overridden by operator input 270, such aswhen the operator increases the throttle position, pushes a brake pedal,or moves a gear level, to re-engage engine 104 to driveline 107 andterminate coasting operation of vehicle 100.

In one embodiment, the transmission gear command 250 is an actuator thatachieves a neutral position of the transmission 106 by using a rangeshift or split shift cylinder to obtain the neutral position. Althoughnot explicitly shown in the figures, it will be appreciated by those inthe technical field that either the range shift or split shift cylindercan be located within the contours of the manual transmission 106 orelsewhere. To set forth one non-limiting example, one or more componentsof either the range or split shift can be located in an auxiliaryhousing, such as but not limiting to an auxiliary housing locatedbetween the manual transmission 106 and the drive shaft 108. A splitterthat is typically used for a manual transmission is actuated by actuator119 to move between high and low split positions so that a neutralposition is obtained. In another embodiment, the actuator 119 arrangesthe splitter so that when fully engaged to the high or low position, aneutral position is obtained since no gear meshes are connected to anoutput shaft of transmission 106, such as drive shaft 108. In yetanother embodiment, a range shift is configured to select neutral inresponse to the transmission gear command 250. Transmission 106 can beconfigured so that actuation to the neutral position is obtained withoutclutch actuation, such as performed in shifting between top gears ofsome currently available manual transmissions.

Although as discussed above the CEM module 150 can be structured tooutput a command to disengage the engine 104 from the driveline 107 inresponse to a coasting opportunity, the CEM module 150 can also bestructured to monitor performance of the vehicle 100 and re-engage theengine 104 to the driveline 107 when conditions warrant. Suchre-engagement can occur when vehicle speed and/or predicted speedexceeds a threshold, the condition of which can be monitored by the CEM150 or other suitable module during the coasting event.

FIGS. 3a-3d depict an embodiment of a coasting control scheme structuredto reduce an engagement/disengagement frequency of the engine 104 anddriveline 107, and extend a coasting event when a temporary speed lossduring the coasting event is predicted to be within a tolerance band.The transmission can be maintained disengaged when vehicle speed loss ispredicted to be within a calibratable band to avoid transmissionengagement if speed is predicted to recover. Shown in FIG. 3a is aschematic of a vehicle 100 on an overall downhill grade having anintermediate uphill segment. FIGS. 3b-3d depict various control schemesincluding a baseline cruise control, an intelligent coasting management(ICM) control scheme (e.g. a standard ICM, or simply ICM), and an ICMcontrol scheme with a horizon look-ahead (e.g. ICM with Horizon). Any ofthe ICM and ICM with Horizon can be implemented in the CEM 150. The ICMwith Horizon control scheme will be described in more detail below, butin general includes the ability to look ahead and use future roadconditions/grade to influence control system actions. Unless otherwiseindicated explicitly to the contrary, as used herein the variousembodiments described below in the other figures in which thedescription refers to future road grades can likewise utilize the fullspectrum of look ahead road information not just limited to road grade,such as but not limited to speed limits, road hazards, etc. In thisembodiment in FIGS. 3a-3d , it is used to influence a reduction inengagement/disengagement frequency. The ICM with Horizon featureddepicted in the figures includes embodiments of the instant applicationwhich assist in reducing engagement/disengagement frequency and extendthe coasting event.

FIG. 3b depicts operation in ICM in line 310 in which the coasting eventis initially ON, is temporarily switched OFF during the intermediateuphill segment, and is then switched ON again after resumption of thedownhill coasting event. The coasting event will be understood as acondition in which the engine 104 is disengaged from driveline 107 inresponse to coasting opportunity, where ON represents a disengagement ofthe engine 104 from the driveline 107, and OFF represents re-engagementof the engine 107 to the driveline 107. The line 320 in FIG. 3b depictsoperation of the ICM with Horizon feature in which the coasting featureremains ON even during the intermediate uphill segment.

FIG. 3c depicts the speed profile of the vehicle in which baselinecruise control is shown in line 330, ICM is shown in line 340, and ICMwith Horizon is shown in line 350. FIG. 3d depicts fuel flow rate of thevehicle in which a baseline cruise control is shown in line 360, ICM isshown in line 370, and ICM with Horizon is shown in line 380. A greenbracket in FIG. 3d illustrates the extension of the transmissiondisengage zone to allow longer periods of idle coasting.

FIGS. 4a and 4b depict similar information to that shown above. FIG. 4ashows the engagement/disengagement of the coasting feature, and FIG. 4bshows the divergence in speed from the set speed (also referred to asthe cruise isochronous speed, or CC_IsochronousSpeed). The line 410represents the set speed. The line 420 represents ICM, and the line 430represents ICM with Horizon. Also shown in FIG. 4 is a Cancel_Deltaoffset from set speed, as well as an additional tolerance Toll beyondthe Cancel_Delta. The Cancel_Delta represents a speed at which thecontrol system (e.g. CEM) will disengage the coasting feature, and thusre-engage the engine 104 to the driveline 107, in light of an excessiveexcursion from the set speed.

The solid line in FIG. 4a represents the ICM coasting feature beingdisengaged when its speed drops to the Cancel_Delta threshold. The ICMwith Horizon feature permits a speed excursion beyond the Cancel_Deltaby looking ahead in the terrain and detecting the intermediate butnevertheless sufficiently short duration rise/change in terrain asdepicted in FIG. 3a . If speed drops below the Cancel_Delta thresholdwhen operating in ICM with Horizon, so long as the predicted speedremains above the Toll line, the coasting feature remains engaged andthus a reduction in engagement/disengagement is realized. The greenbracket in FIG. 4b illustrates the extension of the transmissiondisengagement zone to allow longer periods of idle coasting. A furtherexample of speed dropping below Cancel_Delta but the driveline remainingdisengaged based upon predicted speed during operation of ICM withHorizon is discussed below with regard to FIG. 5.

FIG. 5 depicts similar information to that shown above in FIG. 4, albeitwith an additional tolerance Tol3 used in conjunction with instantaneousspeed. As before, Tol1 is a limit at which the control system willre-engage the engine 104 to the driveline 107 when predicted speed fallsbelow the limit. Tol3 indicates a line at which the control system willalso re-engage the engine 104 to the driveline 107 when instantaneousspeed drops below the line, regardless if predicted speed remains aboveTol1. Thus, in the embodiment depicted in FIG. 5 both Tol1 and Tol3 canbe used in conjunction with one another.

FIG. 5 thus illustrates two separate cases. The line 510 on the leftside of the figure represents instantaneous speed plotted as a functionof time. The ICM with Horizon looks ahead over an estimation distanceDeltaX1 at reference point 555 and predicts speed of the vehicle at theestimation distance. In the first case, the line 520 predicts that speedwill remain above Tol1, thus the engine 104 and driveline 107 willcontinue to be commanded to remain disengaged. However, if instantaneousspeed drops below the Tol3 line even though estimated speed remainsabove Tol1, ICM with Horizon can command re-engagement of the engine 104to the driveline 107. In the second case, the line 530 predicts thatspeed will drop below Tol1, thus the engine 104 and driveline 107 willbe commanded to re-engage.

Predicting vehicle speed can be accomplished in a number of manners, oneof which includes using a physics based model of vehicle forces tonumerically predict a change in speed.

In one embodiment vehicle coasting can be described by an equation thatconsiders a number of forces impacting speed, such as engine forces,braking forces, aerodynamic forces, rolling resistance, road gradeforces, and driveline losses. Such an equation can take the form of thefollowing:

${m_{e}\frac{dv}{dt}} = {F_{engine} - F_{brake} - F_{Aero} - F_{Rolling} - F_{Grade} - F_{Driveline}}$

In one particular embodiment in which the vehicle is coasting the engineand braking forces can be assumed zero. The variables in the aboveequation can be defined as follows:

-   m_(e) is the effective vehicle mass, m_(e)=m+m_(r); m is vehicle    mass; m_(r) is effective inertia mass of the rotating components;-   v is vehicle speed-   F_(engine) is the force from the engine at the wheels,    F_(engine)=(Engine Torque−Accessory Torque)*Axle Ratio*Transmission    Gear Ratio/Wheel Radius-   F_(brake) is the brake force from the service brakes-   F_(Aero) is the aerodynamic resistance force,    F_(Aero)=1/2ρ_(Air)*C_(d)*A*v²; ρ_(Air) is ambient air density;    C_(d) is drag coefficient; A is frontal area.-   F_(Rolling) is the rolling resistance force,    F_(Rolling)=C_(rr)*m*g*cos(θ); C_(rr) is rolling resistance    coefficient [lb/lb]; g is gravitational acceleration; θ is road    angle, θ[rad]=tan⁻¹(Road Grade [%]/100)-   F_(Grade) is the grade or gravitational force, F_(Grade)=m*g*sin(θ)-   F_(Driveline) is the transmission and final drive losses.

Re-arranging the equation and expanding on relevant concepts, theequation can be expressed as follows:

${\left( {m + m_{r}} \right)\frac{dv}{dt}} = {{\left( {T_{Eng} - T_{Acc}} \right)\frac{{AxleRatio} \cdot {TrnRatio}}{R_{wheel}}} - F_{brake} - {\frac{1}{2}\rho \; C_{d}{Av}_{{cur}\mspace{11mu} {speed}}^{2}} - {C_{rr}{mg}\; {\cos (\theta)}} - {{mg}\; {\sin (\theta)}}}$

Where, with the transmission disengaged, engine torque (Teng), engineaccessory torque (Tacc), and Fbrake are zero. Using the Road LoadEquation, it is possible to find out the resultant decelerationa_(i,t)(dV/dt), and we know current vehicle speed v_(t) at a given timet. Assuming that a_(i,t) is constant during a discretized distanced_(Δt), we can use Newton's equation of motion for uniform acceleration:

V _(t+Δt) ² =V _(t) ²+2a _(i,t) d _(Δt) ⇒V _(t+Δt) =√V _(t) ²+2a _(i,t)d _(Δt)

(note: must check that the operand of the square root is greater thanzero to avoid a complex solution)

FIGS. 6a-6d depict an embodiment of a coasting control scheme structuredto provide early engagement of the engine 104 to the driveline 107 toavoid high fueling and acceleration when a relatively large speed lossis predicted that might lead to excessive fueling under standard ICM.Shown in FIG. 6a is a schematic of a vehicle 100 on a downhill gradewhich ends in an abrupt uphill segment. FIGS. 6b-6d depict variouscontrol schemes including a baseline cruise control, an intelligentcoasting management (ICM) control scheme (e.g. a standard ICM, or simplyICM), and an ICM control scheme with a horizon look-ahead (e.g. ICM withHorizon). Any of the ICM and ICM with Horizon can be implemented in theCEM 150. The ICM with Horizon control scheme will be described in moredetail below, but in general includes the ability to look ahead and usefuture road conditions/grade to influence control system actions. Inthis embodiment in FIGS. 6a-6d , it is used to provide an earlyengagement based on elevation profile of the engine 104 to the driveline107 relative to standard ICM. The ICM with Horizon feature depicted inthe figures includes embodiments of the instant application which assistin providing early engagement.

FIG. 6b depicts operation in ICM in line 910 and ICM with Horizon inline 920, where it can be seen that standard ICM remains in a coastingevent longer than ICM with Horizon (in other words, ICM with Horizonengages earlier than standard ICM). The coasting event will beunderstood as a condition in which the engine 104 is disengaged fromdriveline 107 in response to coasting opportunity, where ON in FIG. 6brepresents a disengagement of the engine 104 from the driveline 107, andOFF represents re-engagement of the engine 107 to the driveline 107.

FIG. 6c depicts the speed profile of the vehicle in which baselinecruise control is shown in line 930, standard ICM is shown in line 940,and ICM with Horizon is shown in line 950. FIG. 6d depicts fuel flowrate of the vehicle in which a baseline cruise control is shown in line960, standard ICM is shown in line 970, and ICM with Horizon is shown inline 980. A bracket in FIG. 6d illustrates the early engagement whenusing ICM with Horizon relative to standard ICM. Note that fuel ratespikes in standard ICM, but with early engagement using ICM with Horizonthe fuel rate demonstrates a gradual rise toward the baseline, at leastwith the type of terrain used in the simulation.

FIG. 7 illustrates two separate cases of ICM with Horizon using theearly engagement scheme based on elevation profile and low speed. Line1010 on the left side of the figure represents instantaneous speedplotted as a function of distance. The ICM with Horizon looks ahead overan estimation distance DeltaX2 at reference point 555 and predicts speedof the vehicle at the estimation distance. By way of comparison to thedistance DeltaX1, in the embodiments described herein DeltaX1 can be thesame or different as DeltaX2. In one embodiment the look ahead speedestimation will only be done once the instantaneous speed is below theTol4 line. In the first of the two cases illustrated, line 1020 predictsthat speed will remain above Tol2, thus the engine 104 and driveline 107will continue to be commanded to remain disengaged. However, ifinstantaneous speed during this time drops below the Tol3 line eventhough estimated speed remains above Tol2, ICM with Horizon can commandre-engagement of the engine 104 to the driveline 107. In the secondcase, line 1030 predicts that speed will drop below Tol2, thus theengine 104 and driveline 107 will be commanded to re-engage.

FIG. 8 illustrates two separate cases of ICM with Horizon using anadditional and/or alternative early engagement scheme, but one in whichprovides early engagement for high speed. Line 1110 on the left side ofthe figure represents instantaneous speed plotted as a function ofdistance. The ICM with Horizon looks ahead over an estimation distanceDeltaX2 at reference point 555 and predicts speed of the vehicle at theestimation distance. In one embodiment the look ahead speed estimationwill only be done once the instantaneous speed is above the Tol5 line.In the first of the two cases illustrated, line 1120 predicts that speedwill remain below Tol6, thus the engine 104 and driveline 107 willcontinue to be commanded to remain disengaged. However, if instantaneousspeed rises above another threshold, such as a BottomDroopWidth whichmay be a speed above the Tol6 line, even though estimated speed remainsbelow Tol6, ICM with Horizon can command re-engagement of the engine 104to the driveline 107. In the second case, line 1130 predicts that speedwill rise above Tol6, thus the engine 104 and driveline 107 will becommanded to re-engage.

The reduced frequency re-engagement, early engagement low speed, andearly engagement high speed embodiments described above can stand alonein some implementations, but in other implementations can be combinedwith each other. For example, the reduced frequency embodiment can becombined with either of the early engagement embodiments. Either of theearly engagement embodiments can be combined with any of the otherembodiments. Still further, all embodiments can be combined together inany given implementation.

Various details with respect to certain embodiments of ICM with Horizonare described, such as entry conditions, speed prediction, types ofvehicles contemplated, etc. Objectives include to reduce fuelconsumption and frequency of idle coasting disengage/reengage byprojecting vehicle speed and determining if a speed recovery is expectedtake place. If a speed recovery is expected to take place, keeptransmission disengaged and coast. If a speed recovery is not expected,reengage transmission sooner to reduce torque spikes duringre-engagement. Requirements include an eHorizon system provideslook-ahead data for road grade and transmission integration allowing foridle coasting.

Constraints include entry conditions such as idle coasting is active(ICM Mode=ICM_ACT), eHorizon grade information is present and valid,vehicle speed above (>) tolerance Tol3 (with respect to Cancel_Delta).This considers incorrect speed prediction due to uncertain vehicleloads, environment, road grade or un-modeled dynamics. Also, a fixeddistance prediction window for vehicle speed, e.g. predict vehicle speedat 0.1 km when entry conditions are valid. Other constraints includespeed prediction to predict vehicle speed based on vehicle load (aero,rolling and grade: VPD with grade eHorizon), set keep disengaged flag totrue if predicted speed is above tolerance Tol1 (with respect toCancel_Delta), if predicted speed is below Tol2 (with respect toCancel_Delta) and vehicle speed is belowCC_IsochronousSpeed−C_ICM_VS_Cancel_Delta+Tol4, then re-engagetransmission to reduce torque spikes during re-engagement.

Various inputs and outputs are useful to implement certain embodimentsof ICM with Horizon. Inputs include current vehicle speed V_(current),cruise isochronous speed, grade look-ahead, look-ahead data resolution(there is also a function call to the vehicle parameter determination(VPD) subsystem), MME Mass. Outputs includes remain dis-engaged when:

V _(predicted)>=(Iso−CancelDelta−Tol1) AND

V _(current)<=(Iso−CancelDelta) AND

V _(current)>(Iso−CancelDelta−Tol3).

In addition, outputs include early re-engage when:

V _(predicted)<(Iso−CancelDelta−Tol2) AND

V _(current)<(Iso−CancelDelta+Tol4) AND

V _(current)>(Iso−CancelDelta) OR

V _(current)≤(Iso−CancelDelta−Tol3).

Iso is also cruise isochronous speed.

FIG. 9 is a block diagram of an embodiment of ICM (whether standard ICM,ICM with Horizon, etc).

FIG. 10 is a depiction of Idle Coasting without Horizon and coast zonedetermination logic. In FIG. 10 coast zone 1 is:

Vehicle Speed<(Iso−C_ICM_VS_Cancel_Delta)

Coast zone 2 is:

Vehicle Speed>(Iso−C_ICM_VS_Cancel_Delta) and

<(Iso+T_CC_BottomDroopWidth) with a top re-entry hysteresis of

<(Iso+T_CC_BottomDroopWidth−C_ICM_VS_Hysteresis).

Coast zone 3 is:

Vehicle Speed>(Iso+T_CC_BottomDroopWidth) with an exit hysteresis of

(Iso+T_CC_BottomDroopWidth−C_ICM_VS_Hysteresis).

FIG. 11 is a depiction of Idle Coasting without Horizon and coast zonedetermination.

FIG. 12 depicts a block diagram implementation of one embodiment of IdleCoasting without Horizon for coast zone determination.

FIG. 13 depicts aspects of ICM with Horizon. The disengage zone can beextended below Cancel_Delta if speed is projected to not fall below Tol1line, otherwise engage. The disengage zone is reduced to Tol4 line ifspeed is projected to fall below Tol2 line, and engaged if current speedfalls below Tol3 line.

FIG. 14 depicts aspects of ICM with Horizon. In FIG. 14 the disengagezone is extended below Cancel_Delta if speed is projected to not fallbelow Tol1 line or above Tol6 line, otherwise engage. The disengage zoneis reduced to Tol4 line if speed is projected to fall below Tol2 line,and engaged if current speed falls below Tol3 line.

FIG. 15 depicts a block diagram implementation of one embodiment of IdleCoasting with Horizon.

FIG. 16 depicts a block diagram implementation of one embodiment of IdleCoasting with Horizon.

FIG. 17 depicts an embodiment of Idle Coasting with Horizon in which afew numbered features are described further below. For example, theblock Enable Conditions is labeled with a number “1” which correspondsto a description below related to that topic as shown in FIG. 19 inwhich the Enable Conditions are labelled with a numeral “1.” at the topof the figure. Likewise the number “2” corresponds to a descriptionbelow related to that topic as shown in FIGS. 20-22 in which the “SpeedPrediction” are labelled with numeral “2” at the top of the figure.FIGS. 23, 24 and 25 correspond to the numbered blocks in FIG. 17 muchlike FIGS. 19-22.

FIG. 18 depicts an alternative and/or additional embodiment of IdleCoasting with Horizon in which a few numbered features are describedfurther below. For example, the block “Enable Conditions” is labeledwith a number “1” which corresponds to a description below related tothat topic as shown in FIG. 19 in which the Enable Conditions arelabelled with a numeral “1.” at the top of the figure. Likewise thenumber “2” corresponds to a description below related to that topic asshown in FIGS. 20-22 in which the “Speed Prediction” are labelled withnumeral “2” at the top of the figure. FIGS. 23, 24 and 25 correspond tothe numbered blocks in FIG. 18 much like FIGS. 19-22.

FIG. 19 depicts an embodiment of Enable Conditions listed above in FIGS.17 and 18. Enable Conditions include ICM Mode is Active (==ICM_ACT);eHorizon grade information is valid(RoadAheadGradeDistanceValid>=Estimation Distance, DeltaX1); Logic isEnabled (enable parameter is true, T_ or C_); vehicle speed is aboveCC_IsochronousSpeed−C_ICM_VS_Cancel_Delta−Tol3; and vehicle speed isbelow CC_IsochronousSpeed+T_CC_BottomDroopWidth+Tol6.

FIG. 20 depicts an embodiment of Speed Protection listed above in FIGS.17 and 18.

FIG. 21 depicts an alternative and/or additional embodiment of SpeedProtection listed above in FIGS. 17 and 18.

FIG. 22 depicts an aspect of one embodiment of Speed Protection listedabove in FIGS. 17 and 18. A grade look-ahead vector has a number ofelements: grade_vector [1,2, . . . ,20]. Grade output is equal to thearithmetic mean of the elements i and i+1 of the grade look-aheadvector:

Grade=(grade_vector[i]+grade_vector[i+1])/2.

This assumes that look-ahead resolution is the same as DeltaX1, and assuch the Grade output is equivalent to the average grade in theestimation distance.

FIG. 23 depicts an embodiment of the Keep Disengaged Criterion listedabove in FIGS. 17 and 18. The Keep Disengaged Flag is true if:

V _(predicted,DeltaX1)>=(CC_IsochronousSpeed−C_ICM_VS_Cancel_Delta−Tol1)

AND

V _(current)<=(CC_IsochronousSpeed−C_ICM_VS_Cancel_Delta).

If else, the Keep Disengaged Flag false. Also, the flag is false ifEnable is not active.

FIG. 24 depicts an embodiment of Early Re-engage Zone 1 Criterion listedabove in FIGS. 17 and 18. Zone 1 corresponds to the low speed re-engage.The Early Re-engage Flag (i.e. re-engage transmission) is true if:

V _(predicted,DeltaX2)<(Iso−CancelDelta−Tol2) AND

V _(current)<=(Iso−CancelDelta+Tol4) AND

V _(current)>(Iso−CancelDelta)

If else, keep the Early Re-engage Flag False. Also the flag is false ifEnable is not active.

FIG. 25 depicts an embodiment of Early Re-engage Zone 3 Criterion listedabove in FIG. 18. Zone 3 corresponds to the high speed re-engage. TheEarly Re-engage Flag (i.e. re-engage transmission) is true if:

V _(predicted,DeltaX3)>(Iso+BottomDroopWidth+Tol6) AND

V _(current)>(Iso+BottomDroopWidth−To15) AND

V _(current)<(Iso+BottomDroopWidth)

If else, keep the Early Re-Engage flag false. Also, the flag is false ifEnable is not active.

FIG. 26 depicts possible values for a number of variables, such as Tol1,DeltaX2, etc.

It should be understood that while the use of words such as preferable,preferably, preferred or more preferred if utilized in the descriptionabove indicate that the feature so described may be more desirable, itnonetheless may not be necessary and embodiments lacking the same may becontemplated as within the scope of the invention, the scope beingdefined by the claims that follow. In reading the claims, it is intendedthat when words such as “a,” “an,” “at least one,” or “at least oneportion” are used there is no intention to limit the claim to only oneitem unless specifically stated to the contrary in the claim. When thelanguage “at least a portion” and/or “a portion” is used the item caninclude a portion and/or the entire item unless specifically stated tothe contrary.

1. A method comprising: operating a vehicle in a coasting mode in which a driveline is disengaged from an engine of the vehicle upon command of a vehicle controller, the vehicle controller structured to re-engage the driveline to the engine if instantaneous speed falls below a pre-set speed by a first threshold; computationally determining a predicted future speed of the vehicle as a result of road conditions upon which the vehicle is travelling; comparing the predicted future speed of the vehicle against a threshold; suppressing re-engagement of the driveline to the engine even if the instantaneous speed falls below the first threshold, such suppression based upon predicted future speed satisfying an inequality condition.
 2. The apparatus of claim 1, wherein the predicted future speed of the vehicle is calculated at a pre-selected distance in front of the vehicle.
 3. The apparatus of claim 1, wherein the predicted future speed of the vehicle is calculated from a physics based model of vehicle performance which includes a look ahead window of an upcoming terrain grade upon which the vehicle is predicted to traverse.
 4. The apparatus of claim 3, wherein the inequality condition includes comparing predicted future speed to a second threshold which is greater than the first threshold such that re-engagement is suppressed if future predicted speed remains within the second threshold.
 5. The apparatus of claim 4, wherein the inequality condition includes comparing instantaneous speed to a third threshold which is greater than the first threshold such that re-engagement is also suppressed if instantaneous speed remains within the third threshold.
 6. The apparatus of claim 3, wherein the inequality condition includes: comparing predicted future speed to a future speed lower limit which is lower than the first threshold and re-engaging if the predicted future speed falls below the future speed lower limit; and comparing instantaneous speed to an instantaneous lower limit and re-engaging if the instantaneous speed falls below the instantaneous lower limit.
 7. The apparatus of claim 6, wherein the instantaneous lower limit is a lower speed than the future speed lower limit, and which further includes re-engaging the driveline to the engine when: (1) instantaneous speed remains between the pre-set speed and the first threshold and within a pre-determined offset from the first threshold; and (2) predicted future speed falls below an early engagement threshold.
 8. An apparatus comprising: a coasting controller for a vehicle having an engine structured to provide motive power to the vehicle the coasting controller structured to: command disengagement of a driveline from an engine at a coast speed such that motive power is not delivered to a driven wheel of the vehicle; re-engage the driveline to the engine if current vehicle speed falls below a minimal threshold speed offset from the coast speed; predict a future speed of the vehicle; and suppress re-engagement of the driveline to the engine even if current vehicle speed falls below the minimal threshold speed when the controller detects that an inequality condition is satisfied based upon future speed of the vehicle.
 9. The apparatus of claim 8, wherein future speed is predicted based upon a model of vehicle performance that takes into account aerodynamic resistance, rolling resistance, terrain grade, and driveline losses.
 10. The apparatus of claim 9, wherein the future speed is based upon traversing a length of road ahead of the vehicle.
 11. The apparatus of claim 10, wherein the inequality condition includes comparing the future speed against a future speed threshold which is lower than the minimal threshold speed and suppressing re-engagement if the future speed is above the future speed threshold.
 12. The apparatus of claim 11, which further includes re-engaging the driveline to the engine when current speed is above the minimal threshold and future speed is lower than an early engagement threshold.
 13. The apparatus of claim 12, wherein the early engagement threshold is different than the future speed threshold.
 14. The apparatus of claim 13, wherein the re-engaging the driveline to the engine when current speed is above the minimal threshold further includes the condition that the current speed is within a band above the minimal threshold but where such band is below the coast speed.
 15. An apparatus comprising: a vehicle having an internal combustion engine structured to provide motive power to a driveline; and a vehicle coasting control system configured to regulate engagement of the engine with the driveline to allow for a coasting event, the coasting control system having a speed estimator structured to predict a future speed of the vehicle in light of upcoming road conditions, the coasting control system structured to command disengagement of the engine at a coast speed from the driveline to enable a coasting condition for the vehicle, re-engage the engine to the driveline when current speed is below a threshold offset speed, and to suppress re-engagement of the engine to the driveline based upon future speed satisfying an inequality.
 16. The apparatus of claim 15, wherein the speed estimator includes a physics based model that predicts future speed of the vehicle at a pre-determined distance in front of the vehicle.
 17. The apparatus of claim 15, wherein the inequality compares future speed with a future speed threshold, wherein re-engagement is suppressed when future speed is above the future speed threshold, and wherein the future speed threshold is lower than the threshold offset speed.
 18. The apparatus of claim 17, wherein the vehicle coasting control system, is further configured to re-engage the engine to the driveline regardless if the inequality is satisfied when a current speed of the vehicle falls below a minimal current speed threshold, the minimal current speed threshold lower than the threshold offset speed.
 19. The apparatus of claim 18, wherein the minimal current speed threshold is lower than the future speed threshold.
 20. The apparatus of claim 19, wherein the vehicle coasting control system is further configured to re-engage the engine to the driveline when: (1) current speed is above the threshold offset speed; and (2) future speed is lower than an early engagement threshold. 21-40. (canceled) 